I had thought that the final version would be 500 Wii Points, a one-time fee, when finalized.
If the trial version is a whole 1200 Wii Points, the final version could be that much or even more. That's common sense.
I was going to say something about bandwidth or servers or something, but then I remembered that it's just a browser downloaded onto your Wii, surfing the Internet through your existing Internet connection, meaning that there's no bandwidth/load/whatever issues on Nintendo's part while you surf. So they can't justify it that way.
Well, I guess they calculated that enough people will be willing to pay that much. It's all about the money, they wouldn't charge that much if they didn't think anyone would pay it.
Me, personally? I might pay 1200 if the finalized version is much closer to as good as any browser on my computer and it's a one-time fee. If it costs more than that, I'd be leery. Subscription, definitely not.